This invention is in the field of industrial sewing machines, and more particularly, relates to a control system adapting for semi-automatic operation an industrial sewing machine of the type having basic manual controls.
While it is possible for a skilled industrial sewing machine operator to manipulate the basic manual controls of a sewing machine as well as to guide work fabrics in the stitching of practically any sewn product, the degree of manual skill and the level of coordination required for many sewing operations makes such purely manual control undesirable. Not only is such purely manual control unduely fatiguing for an operator, but also detrimental to the uniformity of the resulting stitched products and conducive to low productivity.
There have been numerous prior efforts in the sewing machine art to relieve the sewing machine operator of the necessity manually to control various aspects of sewing machine operation. For example, needle positioners have been developed which obviate manual inching of the sewing machine by providing a means for positioning the needle responsive to either an operator influenced signal or to a preestablished control setting. Similarly, thread trimming at the completion of sewing operation has been automated, and it is known to perform auxiliary operations such as raising the presser foot automatically.
While these prior efforts have reduced the degree of manual control required of a sewing machine operator, they have none-the-less required a continuous sequence of operator influence for the sewing of a multiple seam sequence which imposes a high level of coordination on the operator and consequently slows productivity and introduces variation in the resulting sewn products.